It's in whatever the onboard currency is. That could be USD or GBP depending on whether you're booked with Princess or Princess UK. (Other lines use other currencies, but since this is the Princess forum, I only listed the Princess lines.)
The end of the world has not arrived. The status match program will have very little effect overall, other than giving a few Silversea cruises a bad case of sour grapes.
There are only a small number of airlines I know of (all of them being Asian airlines) that will make a big deal about middle names. They care more about the name on your ticket matching your frequent flyer account.
You're better off this way. To get the PUP emails, you have to opt in for all marketing emails, which can be as many as six per day. Monitoring this thread is a far better option.
And since there is nothing to distinguish one activity from another, you can use the same screenshot over and over again.
You can choose to pay the extra or not. They're not forcing you to do anything. It's no different than airlines charging a ridiculous premium for a refundable fare.